To firewall pad or not?

[Robsutt]

Starting my rebuild of my 68 Camaro RS Convertible and working steering install so its time prep the firewall for the column install. I’ll be using vintage air and other products to smooth the firewall. So I was about to buy a full pad but MCB mentioned to me that you can use dynamat like products instead on the firewall. While I planned to use it on the floors etc. I never thought of this option for the firewall. So that’s the question... should I use a stock like full pad or use dynomat xtreme or similar product?

[Robsutt]

Also curious if anyone has used or recommends this product.
http://www.quietride.com/web/viewer....mf_catalog.pdf

[XLexusTech]

Here is what I did... lizard skin on floors an inner firewall both the sound and heat coatings
Then dynmat in select spots

[dhutton]

Dynamat is fine to dampen sound but it won’t stop heat much. You also need thermal insulation of some kind. I generally use jute but Dynaliner or Thermozite or any other number of products can be used. Lizard Skin is not going to provide much thermal insulation imho. The precut firewall pads are a good way to add thermal insulation when applied over Dynamat.

Don

[Robsutt]

Do you suggest Thermozite for the firewall versus the pad? I think I’ll use it for the floor as it’s a reasonable price compared to dynaliner that doesn’t publish their R values.

[dhutton]

I like to use the firewall pad because it is precut for the column etc.

Don

[JustJohn]

You can take it for whatever it's worth but I did work for a while manufacturing the NVH parts of BMW and Mercedes interiors including the firewall pads...
There was nothing special about them other than the amount of material used. About 2" of mass loaded urethane foam backed with 1lb/sq ft mass loaded vinyl. The automakers usually apply the damping material themselves before any of the other assembly work is started.
Any of the decent brands of damping material work - they damp vibration. What I see on this site and elsewhere is that most people stop at that point. After the damping layer, a decoupling layer of foam, and a layer of mass loaded vinyl will give you measurable (audible) results.
This guy covers all the technical bases but is a little pricey: https://www.sounddeadenershowdown.co...gaAgYpEALw_wcB

You can get similar (identical) results with products on Amazon:
https://www.amazon.com/Loaded-Vinyl-...ed+vinyl&psc=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/Premium-Acous...stic+foam+roll
https://www.amazon.com/Stinger-RKX36...tinger+damping
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Robsutt]

You can take it for whatever it's worth but I did work for a while manufacturing the NVH parts of BMW and Mercedes interiors including the firewall pads...
There was nothing special about them other than the amount of material used. About 2" of mass loaded urethane foam backed with 1lb/sq ft mass loaded vinyl. The automakers usually apply the damping material themselves before any of the other assembly work is started.
Any of the decent brands of damping material work - they damp vibration. What I see on this site and elsewhere is that most people stop at that point. After the damping layer, a decoupling layer of foam, and a layer of mass loaded vinyl will give you measurable (audible) results.
This guy covers all the technical bases but is a little pricey: https://www.sounddeadenershowdown.co...gaAgYpEALw_wcB

You can get similar (identical) results with products on Amazon:
https://www.amazon.com/Loaded-Vinyl-...ed+vinyl&psc=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/Premium-Acous...stic+foam+roll
https://www.amazon.com/Stinger-RKX36...tinger+damping
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Very helpful! Thanks!

[AB69Z]

Dynamat is fine to dampen sound but it won’t stop heat much. You also need thermal insulation of some kind. I generally use jute but Dynaliner or Thermozite or any other number of products can be used. Lizard Skin is not going to provide much thermal insulation imho. The precut firewall pads are a good way to add thermal insulation when applied over Dynamat.

Don

I've installed the DynaMat to the interior including the roof. At this point I'm concerned about thermal protection. I'm about ready to order my carpet from ACC and I'm wondering if I should order it with the mass backing option or install the Dynaliner or do both the mass backing and Dynaliner.
Do I need to be concerned about too much built up material in certain areas if I use both

[dhutton]

I've installed the DynaMat to the interior including the roof. At this point I'm concerned about thermal protection. I'm about ready to order my carpet from ACC and I'm wondering if I should order it with the mass backing option or install the Dynaliner or do both the mass backing and Dynaliner.
Do I need to be concerned about too much built up material in certain areas if I use both

I like to use both. I use Dynaliner everywhere except where your feet go. There I use jute.

Don

[AB69Z]

I like to use both. I use Dynaliner everywhere except where your feet go. There I use jute.

Don

What thickness Dynaliner are you using over the DynaMat ? As they make 1/2", 1/4", 1/8"
And why the Jute where your feet go and not Dynaliner there?

[Robsutt]

I like to use the firewall pad because it is precut for the column etc.

Don

Got my pad and about to install it and the column. I covered about 60% of the firewall, inside of the upper dash panel, etc with dynamat extreme. I see people with 100% coverage but that seems excessive. Am I mistaken and should cover more of it? I think even dynamat says you really only need 25% or something to stop panel vibration. Thought I’d check in before I go further, last chance type thing. Lol. Will try to post a pic soon.

[Robsutt]

About 80% coverage on right and middle.


About 20% on left where everything mounts. Seems there already has seals and things to stop vibration. ??

[dhutton]

That is correct as far as I know.

Don

[Robsutt]

Got my firewall pad. Needless to say I’m quite disappointed. There isn’t a hole cutout that fits the fusebox (only right side cut). And there’s a million other useless cuts. Seems like it was made to fit several models except mine. Any one know of a good firewall pad for a 68 that has a heater delete?

Here’s my mess...

[dhutton]

I’m not following you because I can see the fuse block hole clearly in your pad. There is only one fuse block location for the first gen cars as far as I know.

Don

[Robsutt]

I’m not following you because I can see the fuse block hole clearly in your pad. There is only one fuse block location for the first gen cars as far as I know.

Don

Yes part of it is there. There are also cuts for a fusebox that is taller and rectangular. Only the top right is actually cut correctly for mine (square). It’s more like a multi-fit pad. I made a template of what the cutout should look like if it were to fit well around the box with no gaps. Will post a pic in a bit. When I cut it correctly it will be a bit of a mess that needs glued or tapped back together. So I think I will get some Mass loaded vinyl and glue as suggested above to seal all the cuts I won’t be using. Other than needed holes I’d prefer the the rest is a solid with no cuts or gaps. Maybe overboard... not sure.

[Robsutt]

Here’s my template on the box...


Here’s my template drawn in black sharpie on the pad. You can see all the cuts that are not used and/or don’t fit. Some are ok. When I cut this hole correctly it will get weak around all those extra cuts. Again maybe overboard... but if I’m going to build the entire car from the ground up just want to do things the best possible way. Labor of love I guess. Lol

[dhutton]

Where did you get that pad? I didn’t find anything like that in a google search. They all had the hole like your template.

Don

[Robsutt]

Where did you get that pad? I didn’t find anything like that in a google search. They all had the hole like your template.

Don

The pictures don’t always seem to be right. This is the one I bought...
https://www.classicindustries.com/pr...parts/c3a.html

But take a closer look and notice the fuse box cutout is wrong in the pic. It’s the long tall rectangle cutout. Not to mention what I received was just stamped with no cutouts (actually that’s a positive since if cut it would be wrong). Most pics on Ricks, Classic, etc seem to show the tall rectangle cutout and not the accurate square box. That just confuses me more. It’s a journey. Lol